There is a growing clinical need for improving the non-invasive diagnostic capabilities of middle ear pathologies in vivo. To address this need, Physical Sciences Inc. (PSI), in collaboration with the Eaton Peabody Lab at the Massachusetts Eye and Ear Infirmary (MEEI), will develop a clinically viable otoscopic imaging system that will employ phase sensitive optical coherence tomography (OCT) to assess three- dimensional structure and sound-induced motion of the middle ear through the intact eardrum. Phase I bench-top testing on human cadaveric temporal bones will include empirical validation of spatial and temporal stability and optimization of the field of view. The PSI/MEEI team will construct a benchtop prototype, acquire and analyze, preliminary data, and continue the development of the imaging hardware and software control. The development of a clinical prototype is proposed in Phase II with tests on selected live subjects and clinic patients.